Year	Percent
1997	0.3802
1999	0.3482
2000	0.4204
2001	0.4099
2003	0.8892
2004	1.537
2005	1.234
2006	0.9238
2007	0.7185
2008	0.7316
2009	1.5825
2010	1.719
2011	1.4445
2012	1.7748
2013	2.3784
2014	2.1536
2015	2.1775
2016	2.2855
2017	2.3303